Port Create Drop components from Greenruhm Web to Greenruhm Connect

[brunomoutinho]

Code for the Create Drop components at Greenruhm Web: https://github.com/Greenruhm/greenruhm-web/tree/master/src/features/create-drop

We're moving the components from Greenruhm Web into Greenruhm Connect because we want to make all the functionality available for clients that want to use Greenruhm.

The components in Greenruhm Connect should:

• [ ] Rely on connect SDK being passed as a prop and use it accordingly;
• [ ] Accept the view component as a prop, defaulting to our design (currently implemented in Greenruhm Web);
• [ ] Have a good documentation on how it should be used (e.g. it should be clear to the user what are the expected props the view component will receive from the controller component that should handle all the logic).

A WIP implementation of Sign Up and Sign In components can be seen in the following PR: https://github.com/Greenruhm/connect/pull/83

[brunomoutinho]

@ericelliott Could you check if there is anything missing in this issue?